394 



Transactions. 



If we now calculate the percentage of records in the various stages, 

 using the method of implication, we obtain the following results : — 



Table VI. 



1 2 3 4 5 16 



Percentage recorde.d from Wangaloa and Hampden 



beds 

 Percentage 

 Percentage 

 Percentage 

 Percentage 

 Percentage 

 Percentage 

 Percentage 

 Percentage 



recorded from Waiarekan 

 recorded from Ototaran 

 recorded from Hutcliinsonian 

 recorded from Awamoan 

 recorded from Kawa Creek beds 

 recorded from Waitotaran 

 I'ecorded from Castlecliffian . . 

 of Recent species 



11 



38 



42 



46 



69 



70 



69* 



77 



67 



* In calculating this percentage the records from the Greta and Awatere beds were excluded 

 and only those from the North Island localities, or records by implication, were used. 



1. Weka Pass stone. 



2. Weka Pass stone and 



combined. 



3. "Grev marls." 



grey marls " 



4. Lower Mount Brown beds. 



5. Main Moimt Brown limestone. 



6. Uppermost Mount Brown limestone. 



7. Greta beds. 



It svill be seen that the analysis favours the correlation of all the beds 

 up to the top of the Mount Brown limestone with the upper Oamaruian, 

 and, if we group together the Weka Pass stone and " grey marls," of all 

 with the Awamoan. Against this we have the positive evidence of the 

 Foraminifera that the Weka Pass stone and " grey marls " are lower than 

 Ototaran, and of the brachiopods that the main Mount Brown limestone is 

 Hutchinsouian. It is obvious, therefore, that the range of the MoUusca 

 is not yet sufficiently known to give confidence in its use in correlation, 

 which tends unduly to favour correlation with the Awamoan. 



If we examine in detail the list of species from the Weka Pass stone, 

 we find that the species which are responsible for the relatively high value 

 of the Awamoan records are only three- — viz., Strutliiolaria spinosa, Turris 

 altus, and Pecten fischeri — all recorded from the Awamoan only. The 

 finding of any two of these, or of the species without any record — -viz., 

 Epitonium rotundum, Lima imitata, Pecten beethami var. B, Pecten wilhmn- 

 soni, Voluta attenuata, and Voluta sp. of. protorhysa Tate — -in the Waiarekan 

 or lower beds would bring the percentage of Waiarekan species up to that 

 of the Awamoan. 



The collections are scarcely large enough to use the percentage of Recent 

 species with« confidence. This method would place the Weka Pass stone 

 with the Wangaloa and Hampden beds, the " grey marls " with the 

 Ototaran, the middle Mount Brown beds again with the Wangaloa and 

 Hampden beds, the main Mount Brown limestone and the uppermost Mount 

 Brown limestone in the Hutchinsonian or Ototaran. A curious coincidence 

 in the percentages is that the uppermost limestone shows a lower percentage 

 than the main Mount Brown limestone, just as do the Target Gully beds 

 compared to the upper Hutchinsonian in Target Gully, and the total 

 Awamoan fauna compared to the total Hutchinsonian fauna of Oamaru 

 and South Canterbury. In the present case little stress can be laid upon 

 this point, as the list from the main Mount Bro'mi limestone contains so 

 many species collected by Park in 1905 from an horizon not quite definitely 

 determined. 



There is still another way in which the moUuscaii evidence can be 

 looked at — viz., from the point of view of the range of the- species within 

 the district. Thus Pecten huttoni and Dentalium solidum range through 



